 These compounds may act by puncturing bacterial cell walls; or by delaying maturation, disrupting metabolism, or preventing reproduction of the pathogen in question.Studies have suggested that the actual mode and sequence of the dismantling of plant cellular components depends on each individual plant-pathogen interaction, but all HR seem to require the involvement of cysteine proteases.The induction of cell death and the clearance of pathogens also requires active protein synthesis, an intact actin cytoskeleton, and the presence of salicylic acid.